Hi zqrlsm,
Jesper, Roger and I have been talking about etching circuit boards with really thick copper layers.
I have PCB blank with 0.42mm (0.0165 inch)copper layers. Ordinary V tools are no good for this
thick copper stuff.
For that you need small diameter endmills, I use 0.5mm (and on occasion 0.4mm) endmills. The trouble
is that they are very fragile and your milling technique needs to be spot on. Additionally carbide endmills
are cheaper the smaller they get until about 3mm, smaller than that they start costing more.
Jesper was contemplating using 0.2mm endmills, that's 8 thou!!!.....but I think he is coming to the conclusion
that it is too ambitious for hobby use.
I have successfully made surface mount boards with this heavy copper with SOIC outlines of 0.6mm between
pads. Amongst the things I have to do to achieve it is use flood cooling. It might sound weird to most people
using isolation routing but flood cooling was the last piece of the jigsaw I needed to make these boards.
Craig